Abstract
There is considerable potential for ASEAN to produce and supply various biodiesel products to the rest of the world due to its natural resource base; however, the use of biodiesel still presents a number of problems which need to be resolved, especially the high price of raw materials and the quality of biodiesel fuels. In view of these limitations, seeking ways to combine various biodiesel raw materials (e.g. edible and non-edible oils) is one strategy that could be used to solve the problems: reducing the economic cost, utilizing the availability of raw materials and improving the quality of biodiesel fuels particularly cetane number, oxidation stability and cold flow properties. In this study, four biodiesel fuels were mixed to create three biodiesel fuel mixtures in differing weight ratios as follows (i) 70% jatropha curcas oil methyl-ester (JME) with 30% palm oil methyl-ester (PME), (ii) 70% JME with 30% coconut oil methyl-ester (CME) and (iii) 75% soybean oil methyl-ester (SME) with 25% PME. Three kinds of mixed biodiesel fuels in form of B10 and B100 together with conventional diesel fuel have been tested in a direct-injection diesel engine. Via analyzing process based on the in-cylinder pressure data and rate of heat release, the obtained results showed that biodiesel fuel mixtures had similar cetane number to diesel fuel; this is the main factor to explain why three biodiesel fuel mixtures were selected to simulate the current used fuel - diesel fuel. Moreover, all mixed biodiesel fuels were comparable with conventional diesel fuel in performance and combustion efficiency. and d Exhaust gas emissions were reduced significantly(e.g. THC, CO and PM). Especially, the reduction of NOx is an interesting issue in this study; this reduction could be explained by the rate of heat release obtained and the use of antioxidant BHA.
Keywords: Cetane number, Performance, Exhaust gas emissions, Combustion, Oxidation stability, Cold flow properties, Mixed biodiesel, Direct injection diesel engine.